Table 7.
Genotoxicity of furan
| Test system | Cells/animals | Concentration/treatment | Result | Comments | Reference |
|---|---|---|---|---|---|
| In vitro (bacteria) | |||||
| Bacterial reverse mutation assay (Ames test) | S. Typhimurium TA98, TA100, TA1535, TA1537 | 33–10,000 μg/plate | Negative | Aroclor 1,254‐induced male Sprague–Dawley rat and Syrian hamster liver S9 | NTP (1993); Mortelmans et al. (1986) |
| Ames test | S. Typhimurium TA98, TA100 |
56–225,000 μg/plate +/− S9 |
Positive: only in TA98 (+S9) |
Positive only at the lowest dose in TA98 Clear effect only + S9 |
Shinohara et al. (1986) |
| Ames test | S. Typhimurium TA98, TA100 | 54, 272, 1,361, 6,807 μg/ plate | Positive: only in TA100 (+/− S9) | Weak effects | Lee et al. (1994) |
| In vitro (mammalian cells) | |||||
| Forward mutation assay | L5178Y tk+/tk− mouse lymphoma cell line | 125–3,800 μg/mL (−S9) | Positive: ≥ 1,139 μg/mL |
Relative total growth was about 77% Not tested: + S9 |
McGregor et al. (1988) |
| SCEs | CHO cells | 1.6, 5, 16, 50, 160, 500 μg/mL |
Positive –S9: 1.6–160 μg/mL +S9: only at 500 μg/mL |
S9 from Aroclor 1,254‐induced Sprague–Dawley rat liver | NTP (1993) |
| CA | CHO cells | 100, 160, 300, 500, 1,000 μg/mL |
Positive −S9: 100–500 μg/mL +S9: ≥ 500 μg/mL |
S9 from Aroclor 1,254‐induced Sprague–Dawley rat liver | NTP (1993) |
| CA | CHO cells | 3 h exposures, up to 13,614 μg/mL +/− S9 from Aroclor 1,254‐induced rat liver | Positive: Chromatid breaks and chromatid exchanges only in the presence of S9 | No information on toxicity | Stich et al. (1981) |
| SCEs | V79‐Mz‐hCYP2E1‐SULT1 cell line | 0.2–1,089 μg/mL | Positive: both V79‐hCYP2E1‐SULT1 and parental V79‐Mz cell line | Unusual constant increase over the whole dose range. Marginal increase in comparison to the parental V79‐Mz cell line | Glatt et al. (2005) |
| Micronucleus assay | Lymphocytes from two non‐smoking women | 136, 340, 511, 681, 1021, 1,361, 6,807 μg/mL +/− rat liver homogenate. | Negative | Aroclor 1,254‐induced rat liver might contain low CYP2E1 activity. Cytotoxicity: 1,361 and 6,807 μg/mL | Durling et al. (2007) |
| Micronucleus assay, tk +/ tk − mutation assay and DNA breaks by Comet assays | L5178Y tk + /tk − mouse lymphoma cell line | 15–211 μg/mL (~ 225–3,100 μM) | Negative | Only assayed in the absence of S9. No cytotoxicity was observed at any of the tested doses | Kellert et al. (2008a) |
| In vivo | |||||
| Sex‐linked recessive lethal assay | Drosophila melanogaster | Feeding (10,000 mg/kg) and injection (25,000 mg/kg) | Negative | – | NTP (1993), Foureman et al. (1994) |
| Unscheduled DNA synthesis in hepatocytes | Hepatocytes from furan‐treated male F344 rats or B6C3F1 mice | Single gavage treatment: 5, 30, 100 mg/kg bw (rats) and 10, 50, 100, 200 mg/kg bw (mice) | Negative | – | Wilson et al. (1992) |
| SCEs in bone marrow | Male B6C3F1 mice | i.p.: 87.5, 175, 350 mg/kg bw (23 h sampling) and 25, 50,100 mg/kg bw (42 h sampling) | Negative | – | NTP (1993) |
| CA in bone marrow | Male B6C3F1 mice | i.p.: 87.5, 175, 350 mg/kg bw (17 h harvest); 62.5, 125, 250 mg/kg bw (36 h harvest) | Positive: only at 250 mg/kg furan with 36 h sampling time (2 experiments) | – | NTP (1993) |
| Micronucleus assay in peripheral erythrocytes (flow cytometer‐based) | BALB/c and CBA mice |
BALB/c mice: i.p. (0, 50, 75, 90, 110, 125, 150, 175, 200, 250, 300 mg/kg bw) and s.c. (0, 150 and 275 mg/kg bw) CBA mice: i.p. (0 and 225 mg/kg bw) |
Negative | No significant depression of cell proliferation in any of the experiments. A single sampling time (42 h) was used | Durling et al. (2007) |
| Measurements of DNA 8‐oxodeoxyguanosine in liver by immune fluorescence | Sprague–Dawley rats |
Gavage (30 mg/kg bw per day, 5 daily doses per week). Time points: 1, 3, 7, 10, 12, 20 days and 1, 2 and 3 months In addition, a 3‐month treatment + 1‐month off was included |
Positive: Increased DNA 8‐oxodeoxyguanosine levels in areas of centrilobular necrosis. Persistence of DNA oxidation after recovery time in areas affected by cholangiofibrosis | – | Hickling et al. (2010a) |
| Micronuclei, SSBs and DNA cross‐links by Comet assays, DSBs by γ‐H2AX foci in the spleen. | B6C3F1 mice | Gavage for 4 weeks with 2, 4, 8 and 15 mg/kg bw per day |
Positive: micronuclei in mitogen‐stimulated splenocytes (4–15 mg/kg) Positive: γ‐H2AX foci (8 and 15 mg/kg) Negative: Comet assays |
All assays gave negative results in quiescent spleen lymphocytes | Leopardi et al. (2010) |
| DSBs by γ‐H2AX foci; SSBs and DNA crosslinks by Comet assays in the liver. | B6C3F1 mice |
Gavage for 28 days (2, 4, 8, 15 mg/kg bw per day, 5 days per week) Single oral dose (15, 100, 250 mg/kg bw) |
Negative: γ‐H2AX foci and Comet assays (28‐day exposure) Positive: DNA breaks and crosslinks (acute exposure at 250 mg/kg bw) |
28‐day exposure: Increased polyploidy in liver cells Increased expression of several DNA repair genes |
Cordelli et al. (2010) |
| DNA adducts, micronuclei, CAs, SCEs and SSBs and DNA crosslinks by Comet assays | F344 rats | Adducts determination: [3,4 14C]‐furan (0.1 and 2 mg/kg bw) for 2 h by gavage. Genotoxicity: Oral administration of 0.1, 0.5 and 2 mg/kg bw per day for 5 and 28 days |
Positive: some evidence of DNA adducts in the liver and kidney Positive: CAs in proliferating splenocytes Negative: micronuclei, CAs, SCEs and Comet assays in bone marrow and peripheral blood |
DNA adducts apparent in 14 C‐furan treated rats are not the same of those induced by BDA (MS peaks are not identical). Some indication of DNA damage in the liver by Comet assay (a reduction of tail moment and tail intensity after 28 days of furan treatment and increased DNA strand breaks after two weeks recovery) | Neuwirth et al. (2012) |
| DNA‐protein crosslinks by Comet assays | Turkey eggs | Furan injection in eggs at 23 days incubation (136–1,360 μg). Hepatocytes preparation 24 h later | Positive: Formation of DNA protein crosslinks | – | Jeffrey et al. (2012) |
| Micronucleus and Comet assay +/‐Fpg and EndoIII in liver and bone marrow. | F344 rats | Gavage for 4 days (2, 4, 8, 12, 16 mg/kg bw per day) |
Positive: Comet assays in the liver (8–16 mg/kg bw per day) Negative: Comet assays in the bone marrow and micronuclei in peripheral blood |
Increased proliferation in the liver. Up‐ and down‐regulation of several DNA repair, apoptotic and cell cycle genes | Ding et al. (2012) |
| Micronuclei in normochromatic erythrocytes and reticulocytes, mutation assays at Pig‐A and Hprt, liver cII transgene mutation assay, liver Comet assay. | Transgenic Big Blue rats | Gavage for 1 and 8 weeks (2, 8, 16, 30 mg/kg bw per day; 5 days per week) and sampling time 24 h after the end of the treatment |
Positive: Comet assay in the liver (16 and 30 mg/kg bw per day) Negative: micronuclei and mutation assays |
Measurements of mutations at Hprt, Pig‐A and cII transgene and micronuclei were performed after 1 or 8 weeks of treatment | McDaniel et al. (2012) |
| Mutations in the cII transgene in the liver | Transgenic Big Blue B6C3F1 mice | Gavage for 6 weeks (15 mg/kg bw per day; 5 days per week, 24 h sampling time) and for 3 weeks (once weekly, 1 week sampling time) |
Negative: no increase in mutation frequency under either treatment condition Positive: changes in mutational spectra |
Small increase in GC>CG transversions (6‐week treatment); a larger shift with increases in GC>TA, GC>CG, AT>TA transversions in the 3‐week protocol | Terrell et al. (2014) |
| Mutations in the gpt transgene and Spi‐ in the liver | Transgenic gpt F344 male and female rats | Gavage for 13 weeks (0, 2, 8 mg/kg bw per day) | Negative: no increase in mutation frequencies. No changes in mutational spectra at the gpt gene | Increased number of GST‐P foci, PCNA+ hepatocytes and cyclin d1 and cyclin e1 at 8 mg/kg bw per day. Cholangiofibrosis observed in the caudate lobe | Hibi et al. (2017) |
| Analysis of Ha‐ras mutations | Liver of furan‐treated B6C3F1 mice | Samples from NTP study (1993) | Positive: 9 Ha‐ras mutations: 4/5 GC>TA transversions at codon 61 and 2 GC>CG + 2 GC>TA transversions at codon 117 | The localisation of Ha‐ras mutations in furan‐treated livers differs from that of untreated animals (100% vs 60% mutations at codon 61 in untreated and furan‐treated animals, respectively). | Reynolds et al. (1987) |
| Analysis of Ha‐ras mutations | Liver tumours induced in infant B6C3F1 mice (adenomas + carcinomas) | Treatment in preweaning mice (day 15): i.p. 400 mg/kg bw (single dose) or 6 doses of 200 mg/kg bw (at day 15). | Positive: only in single dose exp: codon 61 mutations were 23/28 (82%) (vs 1/3 (33%) in parallel controls) (mostly C>A transversions) | Statistically significant increased incidence and multiplicity of hepatocellular neoplasms in the multiple treatment group and only increased multiplicity in the single dose group | Johansson et al. (1997) |
| Analysis of Ha‐ras mutations by ACB‐PCR | Liver of furan‐treated B6C3F1 mice | Gavage: 0, 1, 2, 4 and 8 mg/kg bw per day (5 days per week) over a 3‐week period | Negative: No increase in mutations frequency at codon 61 (CAA>AAA and CAA>CTA) | Relatively insensitive assay | Banda et al. (2013) |
| DNA adduct formation (BDA‐dC adduct) | Serum and liver of furan‐treated Fischer 344 rats | Gavage: 0.92–9.2 mg/kg bw (single dose) and 4.4 mg/kg bw per day (multiple doses, 45–360 days) | Negative: No increase over background levels | Background levels in untreated rats: 1.2–2.4 adducts ×108 nucleotides | Churchwell et al. (2015) |
| 8‐Oxodeoxyguanosine | Serum of furan‐treated Sprague–Dawley rats | Gavage. 16 mg/kg bw per day over 30 days | Positive: large increases in 8‐oxodeoxyguanosine levels | Method: ELISA kit | Alam et al. (2017) |
| ROS and 8‐oxodeoxyguanosine | Serum of furan‐treated BALB/c mice | i.p. 8 mg/kg bw per day over 7 days | Positive: increased ROS levels; threefold increase in 8‐oxodeoxyguanosine | Method: ELISA kit | Wang et al. (2014a) |
A: adenosine; ACB‐PCR: Allele‐specific competitive blocker‐polymerase chain reaction; BDA: cis‐but‐2‐ene‐1,4‐dialdehyde; bw: body weight; C: cytidine; CA: chromosomal aberrations; CHO: Chinese hamster ovary; dC: 2’‐deoxycytidine; DSB: double strand break; ELISA: enzyme‐linked immunosorbent assay; G: guanosine; i.p.: intraperitoneal; ROS: reactive oxygen species; s.c.: subcutaneous; SCE: sister chromatid exchange; SSB: single strand break; T: thymidine.